Die cut mold-in

ABSTRACT

A fastener of the hook and loop type intended to be incorporated into plastic articles by plastic molding processes is formed of a known separable fastener member having a base member and a plurality of engaging elements upstanding from one surface thereof. A vinyl plastisol, thermoplastic, or rubber encasement which intimately surrounds the individual engaging elements protects the elements when they are exposed to the harsh environment of a molding process. The fastener is placed in a mold and molded into, as an integral part thereof, a plastic part. The encasement is removable from the engaging elements after the molding process, to expose the engaging elements, without permanently deforming or substantially destroying the fastening performance thereof.

BACKGROUND OF THE INVENTION

This is a continuation of application Ser. No. 08/390,150 filed on Feb.21, 1995, now abandoned, which is a continuation of application Ser. No.08/087,917 filed on Jul. 6, 1993 now abandoned, and which designated theU.S., which is a continuation in part of application Ser. No. 07/695,183filed on May 3, 1991 now abandoned, and application Ser. No. 07/976,485filed on Nov. 16, 1992 now abandoned, which was a continuationapplication Ser. No. 07/695,183 filed on May 3, 1991 now abandoned.

This invention relates to an improved device and method for adaptingseparable fasteners, particularly those of the hook and loop type, forattachment to other objects such as poly(urethane) foam seat cushions orhard plastic parts for automobiles, furniture and the like. In thismethod one portion of a separable fastener is incorporated into theplastic object during the molding process for subsequent attachment toanother object carrying the mating portion of the separable fastener.The fastener of this invention provides a greater degree of designflexibility as to the shape and especially as to types of plastic intowhich the part may be molded. Although particular reference is madeherein to elastomeric poly(urethane) foam or hard plastic parts, it isto be understood that a fastener product as per this application can beused in parts made from a wide variety of materials, e.g. thermoplasticmaterials, thermosetting materials, elastomers, or any other moldablecomposition, and such compositions are referred to broadly as plastics.

DESCRIPTION OF THE PRIOR ART

Hook and loop separable fasteners, such as those sold by the assignee ofthis application under the trademark "VELCRO" are well known and used tojoin two members detachably to each other. This type fastener has twocomponents. Each has a flexible substrate or base having one componentof the fastening system on the surface thereof. One surface is typicallycomprised of resilient hooks while the other is comprised of loops. Whenthe two surfaces are pressed together they interlock to form areleasable engagement.

The hooks can be of any of a variety of shapes, ranging from simplecane-shaped hooks, to palm tree-shaped hooks, to mushroom shaped hooks,all of which are well known within the art. As used within thisapplication, the term "hook" shall be construed to cover any suchconfiguration of loop-engaging element.

Separable fasteners have in recent years been used in the manufacture ofautomobile seats in the attachment of an upholstered seat cover,hereinafter called trim cover, to a poly(urethane) foam bun. One portionof the separable fastener is incorporated into the surface of thepoly(urethane) seat bun during the foam molding process. The matingportion of the separable fastener is attached to the seat cover toprovide releasable attachment to the foam seat bun. The separablefastener assembly used in the foam mold for incorporation in the bunsurface typically comprises the hooked portion of the separable fastenersystem. This hook portion is characterized by a base carrying resilienthooks on one surface. The outer surface of the base may act as ananchoring surface by a variety of methods well known in the art. In someassemblies a magnetizable shim is attached to the base to facilitateplacement of the assembly in a trough of the mold cavity wall, which isequipped with magnets. A protective layer, usually in the form of a thinplastic film, is placed over the resilient hooks to prevent incursion offoam into the hooks during the molding process. Significant foamcontamination of the hooks would affect their ability to engage with themating portion of the fastener. Such fastening devices are applied toone surface of a clamshell mold; a chemical mixture, usually of adiisocyanate and a polyol, are injected into a mold; the upper surfaceof the mold is closed and clamped shut while the chemicals react andblow to form a flexible foam, well known in the art. The present stateof the art relating to the attachment of such fastener means to foamedseat cushions and the like is generally represented by French patents2,405,123 and 2,423,666 as well as the following U.S. patents:

U.S. Pat. No. 4,470,857, issued Sep. 11, 1984 in the name of Stephen J.Casalou and assigned to R. A. Casalou, Inc.;

U.S. Pat. No. 4,563,380, issued Jan. 7, 1986 in the name of Philip D.Black and assigned to Minnesota Mining and Manufacturing Company;

U.S. Pat. No. 4,673,542, issued Jun. 16, 1987 in the name of Lauren R.Wigner and assigned to General Motors Corporation;

U.S. Pat. No. 4,693,921, issued Sep. 15, 1987 in the name of Patrick J.Billarant and Bruno Queval and assigned to Aplix;

U.S. Pat. No. 4,710,414, issued Dec. 1, 1987 in the name of Walter E.Northup and Maurice E. Freeman and assigned to Minnesota Mining andManufacturing Company;

U.S. Pat. No. 4,726,975, issued Feb. 23, 1988 in the name of Richard N.Hatch and assigned to Actief N.V. ABN Trust Co.; and

U.S. Pat. No. 4,842,916 issued Jun. 27, 1989 to Kunihiko Ogawa et alassigned to Kuraray Company Ltd., Kurashiki, Japan.

Such mold-in separable fastener assemblies presently in use, whileproving to be superior means of attaching a seat cover to a foam bun,have limitations. One disadvantage of the separable fastener assembliesof the type disclosed in U.S. Pat. No. 4,673,542 is that the thinplastic film layer used to cover the hooks is light and flimsy thuslimiting the degree of protection offered to the hooks against highpressure or temperature. Such devices are therefor unable to be used formolding hooks into hard plastic using a standard injection moldingmachine where the high temperature of the molten plastic has a tendencyto melt the hooks or the high pressure of the plastic during theinjection process is capable of crushing the hooks.

Other prior-art assemblies, including those disclosed in U.S. Pat. Nos.4,726,975, 4,563,380 and 4,693,921 also employ a thin layer of film toprevent the incursion of foam into the fastener elements of theseparable fastener during molding. French Patent 2,423,666 discloses asystem for sealing the edges of the tape in the mold trough by jammingthe edges of the fastener into the trough. None of these methodsprovides protection for the hooks against high temperature or pressurewhich will destroy hooks during the molding operation. U.S. Pat. No.4,562,032 incorporates a soft lining as an integral portion of the moldcavity surface to protect the grain of a thin grained face of a vinylsheet but the patent literature is generally devoid of teachings whichprotect large protuberances on plastic mold inserts from the rigors ofthe injection or compression molding process. In fact the patentliterature repeatedly recommends the melting temperature of the insertpart be greater than the processing temperature of the injecting moltenpolymer. Such teachings are contained in U.S. Pat. No. 2,643,158directed to a method of molding brushes. At section 4, line 60-63, "Ingeneral the materials should be selected so that the strands or tuftsshall not be caused to deteriorate by the molding heat". Those skilledin the art understand it is not advisable to insert plastic intoinjection molds or into compression molds at temperatures greater thanthe distortion temperature of the insert part. In some cases methods areused for cooling a portion of the mold containing a meltable insert.Such systems are cumbersome, expensive and difficult to use.

U.S. Pat. No. 2,293,035 describes a method of combining two molded partsof different colors into one article by molding the first mold pieceinto a removable metal insert that constitutes the first part mold andusing the removable mold as the insert in the second mold withoutremoving the first part from the insert mold. The method recommendsmolding the second part while the first part is still warm to achieveproper bond between the first and second parts. This method provides nospecial methods of protecting the part from pressure or temperatureother than to retain it in its original mold. It has the disadvantagethat the first mold is large and cumbersome because of the necessity offitting and being retained securely into the first injection moldingstep.

SUMMARY OF THE PRESENT INVENTION

In the present invention there is provided a novel fastener capable ofbeing insert molded into elastomeric foamed parts, such as seat buns, orinto hard plastic parts such as cases, using standard injection orcompression molding techniques without contaminating or destroying thehook projections due to intrusion of material onto the hooks or heat andpressure. As in the prior art products, the invention carries on onesurface an area of outwardly extending fastener elements, preferablyhooks. These fastening elements constitute one half of a touch fasteningsystem. The other half of the fastening system is attached to thecompanion portion of the intended assembly. The outwardly extendingfastener elements, however, are at least partially encased in anelastomeric compound, more specifically described below, which fillsmost (preferably all) of the void areas surrounding and protecting theengaging elements.

This novel fastener appears as a sheet like structure. In this form, itis possible to cut out strips or segments having complex shapes from thesheet which can be placed into a mold to be molded into a plastic part.According to one aspect of the invention, encasement of the engagingelements is total such that the surface of the encasement is completelyvoid of protuberances. According to another aspect of the invention,encasement is not quite total, such that the top surfaces of theengaging elements are slightly exposed, as through "pinholes." Suchexposure avoids formation of a vacuum seal around the engaging elementsand makes it easier to remove the encasement after the fastener ismolded into a part. The elastomeric encasement possess sufficientresistance to compression to protect the hooks against high pressures ofthe molding process and also provides insulation against transfer ofheat from the molten injected plastic which could melt the hooks of thefastener.

A variety of materials may be used for the elastomeric encasement. Vinylplastisol, preferably foamed, is preferred in certain circumstances.Various extruded thermoplastics may also be preferred, as may severaltypes of rubber.

I have found it convenient to incorporate means for magnetic attractionwithin the elastomeric encasement for holding the fastener against themagnets incorporated into the walls of the mold as is well known in theart. Such materials as iron filings or iron oxide or carbon steel stripsare suitable for such purposes. Alternatively, a steel shim may beincorporated in or affixed to the base member of the fastener orattached to the cover of the fastener.

This invention provides a fastener which is capable of withstanding therigors of the most severe molding processes, such as injection orcompression molding, at temperatures greater than the distortiontemperature of the polymer forming the insert part. A fastener accordingto the invention is placed in a mold and positioned with the aid of themagnets. Material from which the molded product is to be fabricated isintroduced into the mold, and the product is formed by molding. Aftermolding, the elastomeric protective encasement is removed from thefastener elements thereby exposing the hooks. The protective encasement,being elastic, is capable of being removed by several means. In itssimplest form removal is achieved by simply yanking or pulling upon thesheet formed by the elastomeric compound. The elastomeric sheet is ofsuch integrity and elasticity it can be pulled away from the hookswithout distorting them or without breaking itself. Other methods ofremoval are possible including injecting air through a needle insertedthrough the elastomeric protective encasement to lift the encasement offthe engaging elements through pressure built up under the encasement. Inany event the exposed hooks at this point form an integral part of theplastic piece.

The companion portion of the assembly, containing on its inner surfacecompanion fastening elements (loops for example) is affixed to theplastic part by means of the incorporated mating elements. The hook andloop closure firmly holds the two components together providing adetachable means for combining the sections of the assemblage. Thefastener of this invention is also usable in molding situations such asthe cold molding of urethane seat buns.

Applying a vinyl plastisol encasement to a release blanket, then nippingthe hooks into the vinyl plastisol, is a preferred method for producingthe fastener component of the invention. Extruding a thermoplasticencasement into which the hooks are embedded may also be preferred attimes. Furthermore, it can be convenient to apply the protectiveencasement to the fastener material in wide sheets using coating orcalendering techniques well known in the art. It is then possible toslit the wide product into long narrow strips which substitute readilyfor the more conventional well known strip fasteners molded into seatbuns for attachment of trim covers to form a completed seat assembly. Tocreate special shapes of fastener, desirable for more intricate designsin the seat I cut the wide sheet into various shapes, such as curves,chevrons, wings and the like, using methods well known such as rotary orsteel rule dies.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more fully understand the invention, reference is made tothe following detailed drawings.

FIG. 1 is a cross sectional view of hook and loop components of a hookand loop fastener.

FIG. 1a is a cross sectional view of a back-to-back hook component of ahook and loop fastener.

FIG. 2 is a cross sectional view of the hook component of FIG. 1 withthe hooks encased in a protective encasement according to the presentinvention.

FIG. 2a is a cross sectional view of the back-to-back hook component ofFIG. 1a with the fastening hooks encased in a protective encasement.

FIG. 3 is a cross sectional view depicting the fastener component ofFIG. 2 positioned in an injection mold with the mold faces apart.

FIG. 4 is cross sectional view of the mold of FIG. 3 with the moldclosed and having received molten plastic.

FIG. 5 is a cross sectional view of the mold of FIGS. 3 and 4 with themold reopened and ready to discharge a molded plastic part having thefastener component of FIG. 2 molded therein.

FIG. 6 is a cross sectional view of the molded plastic part of FIG. 5demonstrating removal of the elastomeric encasement from the hooks ofthe fastener component.

FIG. 7 is a cross sectional view of the molded plastic part of FIG. 6after the elastomeric encasement has been completely removed.

FIG. 7a is a cross sectional view of a molded plastic part, similar tothat of FIG. 7, made with the back-to-back hook component of FIGS. 1aand 2a.

FIGS. 8-10 depict the same sequence as FIGS. 3-5, but for a compressionmolding process instead of an injection molding process.

FIGS. 11-13 depict a fastener according to the invention being employedin a liquid plastic molding process wherein reactive chemical are pouredinto the mold and react to form a solid foam object, e.g., foam seatbuns for automobiles.

FIG. 14 depicts schematically a knife coating technique for applying theelastomeric encasement compound to the hooks of a fastener tape toproduce a fastener component according to the invention.

FIG. 15 depicts schematically an alternative, calendering technique forapplying the elastomeric encasement compound to the hooks of a fastenertape to produce a fastener component according to the invention.

FIG. 16 is a schematic diagram showing an assembly line for producing afastener component, as in FIG. 2, having a vinyl plastisol hookencasement.

FIG. 17 is a schematic, side elevational view of a knife over rollcoater used in the assembly line of FIG. 16.

FIG. 18 is a cross sectional view showing hook elements protrudingslightly through the elastomeric encasement according to another aspectof the invention.

FIG. 18a is a close up view of a hook protruding slightly through theencasement, as shown in FIG. 18.

FIGS. 19 and 20 are schematic diagrams depicting alternative assemblylines for producing a fastener component, as in FIG. 2, having anextruded thermoplastic hook encasement.

FIGS. 21-23 are cross sectional views showing various embodiments of ahook fastener according to the invention, with a steel shim used forpositioning the fastener within a mold.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a cross-sectional view of the two portions of a standard hookand loop tape 1 where the two portions are not engaged. Base 4 supportsupstanding hooks 2 and loops 3. As the two portions are pressed togetherthe hooks 2 penetrate loops 3 to releasably engage each side of thefastener. Backing 6 has been added to base 4 to serve as a tie layer formolding the fastener 1 into other objects such as plastic parts orelastomeric seat buns. Alternatively, as shown in FIG. 1a, aback-to-back hook portion has fastening hooks 2' which are used tofasten the hook portion to the loop portion; tie-down hooks 6' which areused to anchor the fastener into the molded plastic part; and base 4',all of which are integrally molded. Loops 3 and hooks 2 are customarilymade from thermoplastic polymeric resins which are heat set toresiliently retain their shape during multiple openings and closings ofthe fastener. If the thermoplastic hooks or loops are subjected to hightemperatures and/or high pressures the elements 2 or 3 will be crushedand rendered inoperable. If the temperature is raised near the softeningpoint of the thermoplastic resin forming the fastener elements, theelements will distort or even melt if the temperature is sufficientlyhigh. If at the same time great pressure is applied to the softenedelements the entire assembly is crushed and the function of the fasteneris destroyed.

A typical environment wherein such temperatures and pressures areencountered is in plastic molding such as injection molding, compressionmolding, casting, slush molding, powder molding, transfer molding,rotational molding and the like. Heretofore, it is not known to mold-inhook and loop fasteners directly into plastic parts using such methodsbecause the molding process destroys the fastener elements.

FIG. 2 depicts a cross sectional view of the product of this inventionwherein the above mentioned difficulties have been overcome by encasingthe fastener elements 2 in an elastomeric encasement 7 which completelysurrounds the elements 2. Similarly, FIG. 2a depicts a back-to-back hookportion wherein the fastening hooks 2' are encased in elastomericencasement 7, while tie-down hooks 6' are left exposed to facilitateanchoring the hook portion into a molded plastic part. The elastomericprotection encasing the elements 2 or 2' can be selected from a widevariety of materials which operate to encapsulate and preventcontamination or destruction of the hook or loop projections during arigorous plastic molding operation, while at the same time affording anencasement that can be easily applied and removed from the projectionswithout damage to their ultimate function as a separable fastenerassembly.

Accordingly, elastomers are selected which have an initial applicationviscosity that facilitates the diffusion and penetration of theelastomer resin into the tiny irregularities of a hook and loopfastener. Both solvent cast and two-component curing elastomer systemsare broadly contemplated, wherein the application viscosity of theformer can be conveniently adjusted by controlling the weight percent ofsolid elastomer contained within a particular solvent system. In anembodiment using a two-component curing elastomer system, the individualliquid component viscosity becomes an important consideration forselecting the particular reactive combination. Accordingly, the uncuredliquid components must combine to provide an application viscosity thatfirst penetrates and encapsulate a fastener element, prior to eventualcuring and formation of a solid encapsulating elastomeric medium.

Still a further criterion for selecting the elastomers of the instantinvention is to include those elastomers that are effective to keepmolten or liquid plastic out of the fastener elements during aparticular molding cycle yet do not become permanently bound to thesurface of the hooks or loops such that their removal destroys thefastener assembly. In connection with this objective, elastomers areselected which are relatively unable to adhere permanently to thesurface of the particular fastener elements which they areencapsulating. It will also be appreciated that various additives can becombined with a particular elastomer to minimize permanent bonding ofthe surface of the fastener with a particular encapsulating material.Alternatively, the surface of the particular fastener may be treatedwith a release agent, prior to being coated with an elastomer resin,which facilitates removal of the elastomer after the plastic moldingcycle is complete. Furthermore, additives may be incorporated directlyinto the various materials employed to produce the fasteners themselves,which would also contribute to a reduction in the bonding between thefastener surface and the encapsulating resin.

In addition to bonding performance, it is important to consider thestructural characteristics of the elastomer as well. The elastomer mustbe soft or pliable enough (as indicated by Shore A durometer value orflex modulus) so as to be peeled away from the fastener. At the sametime, it must possess sufficient tensile strength such that it does notbreak when being pulled away from the fastener.

Elastomers that are particularly suited to satisfy the aboverequirements include silicone rubbers, but other suitable materialsinclude, when properly compounded, natural rubber, urethane rubbers, orother elastomers well known in the trade. When properly applied onto ahook and loop fastener 1 the elastomer encases the elements 2 (or 3)around all sides and effectively holds the element 2 in place withrespect to its base 4 and adjacent hooks 2. The encapsulating elastomer7 acts as both a seal to keep molten or liquid plastic out of the hooks2 or loops 3 during the molding cycle, and as a compression stay tocushion the hooks from the extreme pressures associated with plasticmolding cycles, and as an insulation barrier from any heat distortion ormelting.

FIG. 3 is a cross section view of a simple injection mold 8 showingcavity plate 9 and core plate 10 in the open position. Fastener 5 isinserted into a section of the core plate and held thereon by a magnet13 which is made an integral part of the mold 8. To assure attractionbetween the magnet 13 and the fastener 5, elastomeric encasement 7contains, in addition to the elastomeric compound, iron particles thatwill be attracted to the magnet 13 and hold the fastener 5 in thedesired location. FIG. 4 is a cross section representation of the mold 8in the closed position where plastic has been injected into the cavity 9through opening 11 to create the impression 12. FIG. 5 shows the nextstep in the molding process wherein the mold 8 is opened after theinjected plastic has had time to solidify. At this point the part wouldbe ejected from the mold 8. FIG. 6 depicts the step of removing theelastomeric protector 7 from the plastic part 12 to uncover fasteningelements 2 or 3. FIG. 7 illustrates a cross section of the final piece12 with hooks 2 aligned to receive loops from a companion piece (notshown) to detachably connect the assembly. Similarly, FIG. 7aillustrates a cross section of a final piece 12' made using aback-to-back hook component as shown in FIGS. 1a and 2a. The fasteningelements are unaffected by the severe environment within the mold cavityand are in condition to perform their fastening function when joinedtogether with the companion loop elements.

FIGS. 8-10 depict the molding sequence involved in the compressionmolding process using the fastener of this invention. In FIG. 8, theprotected fastener 5 has been attached to the mold 15 by magnet 13. Apolymer slug 14 is charged to the mold 15 and the upper portion of themold 16 closes against the slug 14 causing it to melt and flow into theunoccupied portions of the mold cavity. FIG. 10 illustrates the nextstep in the compression molding process whereby the mold 15 is openedexposing the piece 12 which is subsequently removed from the mold 15.The finished piece contains the fastener 5, with the elastomericprotector 7 still in place, integrally contained as a part of thefinished molded piece 12. The elastomeric protector 7 is removed asshown in FIG. 6 and the part 12 is represented, as in the case ofinjection molding, by FIG. 7.

FIG. 11 illustrates the use of the invention in a liquid moldingprocess, such as is used for the manufacture of elastomeric seat bunsfor automobiles, wherein the plastic piece 18 (see FIG. 13) is formed bypouring reactive chemicals 17, such as polyol and diisocyanate, into amold 16 and permitting the parts to react to form a solid foam object18. Mold 16 is charged with an appropriate chemical mixture 17, wellknown in the art, covering a fastener element 1 possessing a protectiveencasement 7. The fastener is held in the mold by magnetic attraction ofa magnet 13 imbedded in the mold 16 upon iron particles incorporatedinto the protective encasement, as described above. FIG. 12 shows themold 16 after the chemicals 17 have reacted and filled the mold 16 toform the plastic part 18. FIG. 13 shows the finished part 18, forexample a seat bun, with the fastener 1 positioned in place andintegrally molded therein, after the protective encasement 7 has beenremoved. It will be understood by those skilled in the art that in likemanner any other method of forming plastic parts could be used toincorporate a hook and loop fastener into a solid flexible plastic part.

It may be appreciated from the foregoing discussion that the essence ofthe invention is the provision of the elastomeric encasement around theengaging elements. Both the nature of the elastomeric compound and themethod of its application are important considerations in creating thisnovel fastener. FIG. 14 illustrates a method of applying a liquidcomposition to the fastener elements of the instant invention. Thefastener tape 1 is passed under the knife of a knife coater 19, wellknown in the art. The elastomeric compound 5 is evenly spread over andthroughout the fastener elements 2. A compound composed of Silastic E, atwo part room temperature vulcanizing silicone mixture sold by the DowCorning Company, is ideally suited for application in this manner. Afterapplying the liquid compound it is dried in an oven at 150 F. for 30minutes. The fastener thus treated has a rubbery material completelyencapsulating the fastening elements. A sheet of the encasement has atensile strength of 700 psi and an elongation of 400%. In general, theelastomeric encasement should have a tensile strength of at least 200pounds per square inch, and an elongation of at least 100%.

FIG. 15 illustrates a second method of applying an elastomericencasement to the fastener material to create the product of thisinvention. Calender coating is well known in the art and I have found ituseful for the purposes of coating hook and loop materials. The uncoatedfastener 1 is passed between calender rolls 20. An elastomeric compound7 is applied into the nip 21 formed between the rolls 20. Theelastomeric compound is evenly distributed throughout the engagingelements 2. The combination thus formed is cured in a manner dictated bythe particular elastomeric compound used.

Other materials which are also well suited to this method of applicationinclude Conap Conathane (TU4011), a two part urethane mixture, and vinylplastisol sold by Coating Systems, Inc. (CS8-1303A). To each of thesematerials may be added 25% by weight of Bayflex 316 iron oxide powder asthe ferromagnetic material which is attracted to the mold wall magnet.

Vinyl plastisol has been found to be particularly well suited for use inthe present invention and is therefore a preferred material from whichto form the encasement. A method for producing a mold-in fastenercomponent with vinyl plastisol will now be described with reference toFIG. 16. First, a fiberglass/silicone release blanket 51 is loaded ontounwind stand 50 in roll form and threaded through the processingapparatus. From unwind stand 50, release blanket 51 passes to coatingstation 52.

Coating station 52 is essentially a knife over roll coater, as shown ingreater detail in FIG. 17. Trough 53 is located above rubber roll 54,and release blanket 51 passes between them. As release blanket 51 passesunder trough 53, vinyl plastisol at room temperature is dispensed fromtrough 53 onto release blanket 51. Magnetite (Fe₃ O₄)--for magneticattraction to the mold wall magnet--is also mixed into the plastisol. Asthe vinyl plastisol is applied to the release blanket 51, it is meteredto a specific thickness by metering knife 56 which is attached to trough53.

From coating station 52, release blanket 51 with the vinyl plastisolmaterial enters heated oven zone 58. Oven zone 58 consists of a seriesof infrared lamps and forced hot-air convection ovens which heat thevinyl plastisol to the fusion temperature, which is approximately 375°F. Once the vinyl plastisol is fused, a series of infrared lampsactivate a blowing agent contained in the vinyl plastisol material. Atypical blowing agent is azodicarbonamide, available from the UniroyalChemical Company under the trade name Celogen AZ™. When the blowingagent reaches its activation temperature, it releases nitrogen gas whichcauses the vinyl plastisol to foam, a condition which is preferred.After foaming has taken place, release blanket 51 and the foamed vinylplastisol exit oven zone 58.

From oven zone 58, vinyl plastisol-carrying release blanket 51 passes tonipping station 60 where engaging elements--on a tape of fastenerengaging elements fed from unwind station 62--are nipped into the vinylplastisol while the vinyl plastisol is still soft. The engaging elementsare preferably hooks. The distance from oven zone 58 to nipping station60 is a critical process parameter. When the vinyl plastisol material onrelease blanket 51 exits oven zone 58, it is in the fused and blownstate, but it is still a soft material. If the hooks are nipped into thevinyl plastisol material too early, the vinyl plastisol will be so softthat, once it "cures," it will bond to the hooks so firmly as to preventeasy removal of the encasement. If nipping station 60 is too far awayfrom oven zone 58, the vinyl plastisol will have cooled and hardened tosuch a degree that the hooks can not be nipped into the vinyl plastisolmaterial efficiently, i.e., they will not readily penetrate the vinylplastisol with the proper degree of encasement.

Once the vinyl plastisol, release blanket 51, and hooks are nippedtogether at nipping station 60, they continue through a series of rollswhile the vinyl plastisol cools. At point 64, release blanket 51 isseparated from the vinyl plastisol-encased hooks and is rewound atlocation 66. It is crucial for the vinyl plastisol to have cooledsufficiently such that, once it is separated from release blanket 51, itdoes not stick to anything, especially as the vinyl plastisol-encasedhooks are rewound at location 68. Cooling need not be entirelycompleted, however, before the encased hooks are rewound; final "curing"is in situ, i.e., with the hooks embedded, as the rolled up materialcontinues to cool to room temperature.

When fully "cured," the vinyl plastisol must have sufficient tensilestrength such that, after the fastener has been molded into a part, thevinyl plastisol does not break as it is peeled off of the hooks. Thisconsideration must be balanced against the need to have favorablerelease properties. Ideally, the lowest possible pull off force would becoupled with the highest tensile strength. Softness and rigidity of thevinyl plastisol should be considered, as the softer the vinyl plastisolis, the more easily it will deform around and release the hooks. Tensilestrength should be at least 200 psi. Softness as measured on the Shore Adurometer scale should be less than 90, and a value less than 70 ispreferred.

In its just-foamed state, the vinyl plastisol layer should be justslightly thicker than the height of the hooks, as measured from the basemember to the top of the hooks. For example, where the hooks are 0.13inches high, a foam layer 0.14 inches high is appropriate. As nippingthe hooks into the vinyl plastisol is done under pressure, some of thefoam is collapsed such that a small portion of the hooks, e.g., the verytop surfaces, pushes its way through the vinyl plastisol layer, creatingan array of "pinholes" in the top of the vinyl plastisol layer, as shownin FIGS. 18 and 18a. It has been found that these "pinholes" makeremoval of the encasement easier, as it is believed that they prevent asuction force from forming as the hooks are pulled out of theencasement. Ease of removal and removal without breaking are importantfeatures of the present invention, as such qualities preventmanufacturing slowdown when a fastener according to this aspect of theinvention is used in an assembly line environment.

Although the hooks could be protected using either foamed or solidmaterial, using foamed vinyl plastisol has been found to be advantageousfor a number of reasons, the first of which is cost. By using a foamedmaterial, expensive solid material is "replaced" with nitrogen gas.Second, foamed material protects the hook from the pressure generatedduring an injection or compression plastic molding process. In effect,the foam acts as a compression stop around the hooks. When pressure fromthe plastic material is applied against the back of the fastenerproduct, the foamed vinyl plastisol material will deform and flattenslightly, eventually reaching a point where it protects the hooks frombeing deformed or crushed by the pressure of the molding process.

The foamed material is a closed cell foam, such that nitrogen bubblesare encapsulated within the vinyl plastisol material. This furtherenhances the ease which the encasement is removed from the hooks asbubbles of gas--as opposed to vinyl plastisol--contact the surface ofthe plastic hooks in many places.

As noted above, the vinyl plastisol protective encasement has magnetitedispersed throughout. The magnetite will be attracted to a magnet, suchas a rare earth magnet, that is bonded into a trench in the wall of aplastic-shaping mold. An appropriately cut and shaped piece of mold-infastener product, as made according to the above described process, isplaced into the mold with the elastomeric encasement facing the magnetsand the mold wall. Plastic material is then introduced under pressureaccording to any of the plastic molding techniques described above.

As noted previously, the elastomer protects the hooks from thecompressive force of the molding process. In an injection moldingprocess, the pressure may range from 500 to 2000 pounds per square inchexerted against the hook fastener, depending on the particular materialbeing molded and the molding process itself. In compression molding--aprocess wherein a preheated and softened plastic slug is forced to flowunder pressure into all niches of the mold--the pressure exerted againstthe hook fastener may range from 1000 to 2000 psi.

When the plastic molding process is complete, the mold is opened and themolded plastic part is removed from the tool. At that point, the vinylplastisol elastomeric encasement is stripped from the hooks. As notedabove, the softness of the vinyl plastisol material and the fact that ithas been foamed increase the ease with which it may be stripped from thehooks, as compared to the "strippability" of a harder of more rigidencasement material. Furthermore, it is important that the hooks not bepermanently deformed as the vinyl plastisol encasement is removed, asthat would destroy their fastening capability. The softness,flexibility, and foamed state of the vinyl plastisol further thisobjective as well.

In another preferred manufacturing technique, a thermoplastic materialis used for the encasement and is extruded onto the hooks. As shown inFIG. 19, the technique entails processing a thermoplastic material in anextruder 70, passing it through a slot-form extruder die 71 to form amolten plastic sheet 72 which is used to form the encasement for thehooks. A tape of hooks is unwound from unwind station 73 and the hooksare embedded into the still-soft thermoplastic sheet 72 by nip rolls 74.As in the method described above for providing a vinyl plastisolencasement, when the engaging elements are nipped into the thermoplasticsheetform web, the thermoplastic should be soft enough to permitefficient nipping, yet cool enough to prevent excessive bonding of thethermoplastic to the engaging elements. The composite hook/encasementstructure is taken up at wind-up station 75, after having been cooled at76 between nip rolls 74 and wind-up station 75.

Cooling can simply be by a combination of radiation and convection underambient conditions, but preferably, in most instances, a cooling deviceis employed for this purpose. The composite structure is immersed orpassed through a cooling trough filled with water, or passed through aplenum having cooled air or over a sequence of chilled rolls.Alternatively, cooling can be effected by cooling nip rolls 74 by flowof a cooling medium through their interiors.

The thermoplastic can consist of any of a variety of materials, selectedto ensure sufficient flexibility and cohesiveness to enable strippingfrom the hooks without causing damage to the hooks or the base sheet towhich they are attached or creating risk that the plastic strip mayrupture under pull-off stress. Depending upon the size and distributionof the hooks, the thermoplastic can be a flexible PVC extrusioncompound, a thermoplastic elastomer or other flexible thermoplasticcompounds. The extruded thermoplastic material can be solid or foamed,depending on the particular application of the final product. Asdescribed above with respect to a vinyl plastisol encasement, a foamedencasement yields a cost advantage and can be easier to remove. Anadditional advantage of using a thermoplastic material is the fact thatthe encasement may be recycled after it has been stripped from thehooks.

For certain extruded materials and conditions, the melt strength of theextruded sheet may be so low as to cause sagging of the web if theextruder is disposed horizontally. In such cases, the thermoplastic canbe extruded from a vertical extruder into an upwardly facing nip toavoid sagging of the web.

An alternate method, shown in FIG. 20, employs a release blanket 77.Extruder 70' and extruder die 71' produce thermoplastic web 72', whichis carried by release blanket 77. Hooks of hook tape 73' are embeddedinto the upper surface of the extrudate being carried by release blanket77, and the composite assembly enters the nip formed by rolls 74'. Thecomposite assembly then passes through a cooling device 76', such asdescribed above. From there, it passes to separating roll 78, at whichpoint the release blanket is stripped from the encased hooks and each istaken up separately, take-up station 75' being provided for the encasedhook tape and take up station 79 being provided for the release blanket.

As in the case of a vinyl plastisol encasement, criteria for selectingthe particular thermoplastic material include high flexibility and lowbond strength, so as to permit easy removal of the encasement. Othercriteria include the melting or softening point of the thermoplasticmaterial, which usually is desired to be higher than the temperature towhich the encased hooks are exposed during the molding process, as wellas the tensile strength of the material as noted previously.

In the methods described above, the hooks may be of molded form,including mushroom-shaped, or they may be textile monofilament cuthooks. Furthermore, as noted above, magnetizable matter, e.g. magnetite,can be incorporated into the encasement. This is particularly preferablewhere the hooks are part of a back-to-back configuration as shown inFIGS. 1a and 2a. Substances such as iron powder, iron filings, otheriron oxides such as Fe₂ O₃, other iron compounds, or compounds of otherelements which are magnetizable can be used.

The magnetically attractable substance is advantageously used as ameaningful colorant. For example, iron oxide is available as a pigmentin several colors, such as black, red, and yellow. According to anotheraspect of the invention, different colored oxides are selected for usewith respectively different hook products to identify different sized orshaped fastener mold-ins. Furthermore, by choice of the magnetizablesubstance providing an encasement of a different color than the hooksenables one to tell quite easily, simply by looking, whether or not theencasement has been removed from the hooks.

While in certain preferred embodiments the magnetizable material isdispersed in the material of the encasement, in other circumstances itis preferred to provide it using conventional techniques. A steel shim80 may be attached to the back of the hook base member 4, as shown inFIG. 21, or embedded within the base member 4 as shown in FIG. 22.Alternatively, steel shim 80 may be attached to encasement 7, as shownin FIG. 23. The ferromagnetic substance represents at least 1% of theweight of the covering and preferably between 15% and 25%, inclusive, ofthe weight of the covering.

Reference has been made above to the fastener product being die-cut intovarious shapes. The ability to die-cut the product is obtained, forexample, by extruding a wide hook web of, e.g., twelve inches width ormore, and providing a correspondingly wide encasement. Complex, curved,or very wide shapes can then be die-cut from such a product.

Uses or applications for this product include attaching automotiveupholstery, where a hook assembly is molded into a polyurethane foamseat cushion and then used to attach the fabric or upholstery coveringto the cushion. The potential uses, however, are far broader. A fastenerproduct according to the invention can be used in virtually anyapplication where it is desired to mold hooks into a plastic or rubberpart to provide means for attaching another part to the plastic part.

Furthermore, although the invention has been described in reference toprotecting hooks in an elastomeric encasement, in certain applicationsit may be desirable to apply the encasement to protect loops. Thecharacteristics of the material being molded, as well as thecharacteristics of the loops themselves should be taken into accountwhen determining the advisability of this approach.

EXAMPLES

The following examples will be illustrative of the execution of themethod for manufacturing and use of the product of this invention.

Example I

A length of the plastic hook portion of a hook and loop closuredesignated as Ultra-mate HTH 708 is extruded as described in Fisher U.S.Pat. No. 4,794,028. The resultant poly(propylene) layer containing about750 hooks/in² was coated in a laboratory coater using Dow CorningSilastic E two part room temperature vulcanizing (RTV) silicone mixed ina 10:1 ratio of part "A" with part "B" as recommended by the chemicalmanufacturer. 25% by weight of Mobay Bayferrox 316 was added to thesilicone mixture. The knife of the coater was set to a gap of 0.010"above the top surface of the hooks of the fastener tape for applying afirst coating to the tape. The knife gap was adjusted to 0.025" abovethe top surface of the hooks to render the second coating smooth andmore evenly distributed throughout the hooks. The coated tape was placedin a convection oven at 140 F. for 30 minutes. After removing from theoven and permitting to cool it was observed the silicone encasement waseasily removed from the hook elements with no noticeable distortion ordiminution of their fastening ability. A sample, prepared as described,was cut into a section 1" by 1" and inserted into a recess of the samesize cut to accommodate the fastener, in a plaque mold 1" by 4". A Zytel(nylon) injection grade plastic, sold by the Dupont Company, wasinjected into the mold at a nozzle temperature of 525 F. for 3 secondsat an injection pressure of 7000 psi with a hold time of 45 seconds. Theplastic plaque thus formed was removed from the mold and the siliconeencasement on the fastener was mechanically pulled from the piece toexpose the hooks. No damage to the hook could be observed.

Example II

A length of the plastic hook portion of a hook and loop closure,designated as Ultra-mate HTH 708 poly(propylene), was coated in alaboratory coater using Dow Corning Silastic E, a two part roomtemperature vulcanizing (RTV) silicone mixed in a ratio of 10:1 asdescribed above. 25% by weight of Mobay Bayferrox 316 iron oxide powderwas added to the silicone mixture. Coating proceeded as in example I. Asample cut into a section 1" by 1", was inserted into a recess of thesame size cut to accommodate the fastener, into a plaque mold 1" by 4".A poly(propylene) injection grade plastic, sold by the Dupont Companywas injected into the mold at a nozzle temperature of 425 F. for 3seconds at an injection pressure of 12,000 psi with a hold time of about30 seconds. The plastic plaque thus formed was removed from the mold andthe silicone encasement on the fastener was mechanically pulled from thepiece to expose the hooks. No damage to the hooks could be observed.

Example III

A plastic hook was extruded as in Example I but the plastic was apolyester based elastomer, CFM Hytrel 8238, sold by the Dupont Company.Laminated on the surface opposite the hook elements was a rayon nonwovenfabric, Pellon 850, sold by the Freudenberg Company. The fastenerelement thus formed was calender coated using a proprietary EPDM(ethylene-propylene rubber) material supplied by JPS elastomers divisionof the JPS Corporation who also carried out the calendering step. TheEPDM encasement with the fastener strip was 0.120 inches thick and 12inches wide. Samples of the coated fastener were die cut into shapedpieces approximately 1" wide making a smooth curve with inner radius of20 inches and a total length of approximately 8 inches. The part thuscut was placed in a clamshell mold used to make seat buns incorporatinga pedestal containing a magnet on its upper surface to hold the piecewith the elastomeric encasement facing downward and in intimate contactwith the top surface of the pedestal. A standard charge of liquidchemicals, including a diisocyanate and a polyol, were introduced intothe mold. The upper half of the mold was closed and the chemicalsallowed to react to create a foam which filled the cavity of the mold.The mold was opened and seat bun removed. The EPDM elastomericencasement of the hooks was removed by gripping one end of the elastomerand pulling the encasement from the fastener. The encasement pulled awayfrom the hooks of the fastener without difficulty to expose the hooks.There was no noticeable tendency to pull the fastener from the softurethane foam and the hooking elements were perfectly clear and free ofany chemical. No damage or distortion of the hooks could be observed.

Example IV

A plastic hook (Velcro® hook #CFM 24-2014) was extruded as in Example I,but using Zytel FX4209, a nylon based resin, sold by the Dupont Company.Loop 3200, a polyester knitted loop fabric sold by Guilford, waslaminated on the surface opposite the hook elements. The fastenerelement thus formed was transfer coated using a vinyl plastisol materialfilled with 15% by weight Bayferrox 318M magnetite, sold by Mobay. Theplastisol material also contained a heat activated blowing agent whichcaused the vinyl plastisol to foam when heated. The entire custom-madecomposition was supplied by Coating Systems, Inc. under the productnumber CSI 1341a.

The vinyl encasement with the fastener strip embedded therein was 0.120"thick by 13" wide. Samples of the coated fastener were die cut intoshaped pieces, approximately 1" wide, having smooth curves and variousinner radii and lengths. The pieces were placed in a clamshell mold,used to make seat buns, having a pedestal with a magnet on its uppersurface to hold the piece with the vinyl encasement facing downward andin intimate contact with the top surface of the pedestal.

A standard charge of liquid chemicals, including a diisocyanate andpolyol, was introduced into the mold. The upper half of the mold wasclosed and the chemicals were allowed to react to create a foam whichfilled the cavity of the mold. The mold was opened and the seat bunremoved.

The vinyl encasement was removed from the hooks by gripping each end ofa slit cut through the vinyl in the center of each part, and pulling theencasement from the fastener. The encasement pulled away from the hooksof the fastener, without difficulty, to expose the hooks. There was nonoticeable tendency to pull the fastener from the soft urethane foam andthe hooking elements were free of any chemical. No damage or distortionof the hooks could be observed.

Example V

A plastic hook (Velcro® hook #CFM 24-2014) was extruded as in Example Ibut using Zytel FX4209, a nylon based resin, sold by the DuPont Company.Loop 3200, a polyester knitted loop fabric sold by Guilford, waslaminated on the surface opposite the hook elements. The fastenerelement thus formed was nipped onto an elastomeric, extruded polyvinylchloride (PVC) material filled with 20% by weight Bayferrox 318Mmagnetite, sold by Mobay. The entire custom-made PVC composition wassupplied by Teknor Apex under part number 93-A0090B-52. The PVCencasement with the fastener strip was 0.120" thick by 1" wide.

Samples of the coated fastener were die cut into 1" wide strips ofvarious lengths. The cut pieces were placed in a clamshell mold, used tomake seat buns, having a trench with a magnet on its lower surface tohold the piece with the encasement facing downward and in intimatecontact with the bottom surface of the trench.

A standard charge of liquid chemicals, including diisocyanate and apolyol, was introduced into the mold. The upper half of the mold wasclosed and the chemicals were allowed to react to create a foam whichfilled the cavity of the mold. The mold was opened and the seat bunremoved.

The PVC encasement of the hooks was removed by gripping each end of theelastomer and pulling the encasement from the fastener. The encasementpulled away from the hooks of the fastener, without difficulty, toexpose the hooks. There was no noticeable tendency to pull the fastenerfrom the soft urethane foam and the hooking elements were free of anychemical. No damage or distortion of the hooks could be observed.

What is claimed is:
 1. A hook or loop component of a hook and loopfastener which can be integrally molded into a plastic article by amolding process, said hook or loop component comprisinga fastenerelement comprising a base member and a plurality of engaging elementsupstanding from a surface thereof, a removable, elastomeric protectiveencasement having said engaging elements embedded therein, saidprotective encasement at least partially intimately surrounding saidengaging elements so as to protect said engaging elements during saidmolding process, and a magnetizable substance carried by said fastenerelement for enabling said hook or loop component to be held within amold during said molding process by magnetic attraction to magnets inthe mold, said protective encasement being removable from said engagingelements so as to expose said engaging elements without permanentlydeforming said engaging elements or substantially destroying fasteningperformance of said engaging elements.
 2. The component of claim 1, saidfastener element further comprising a plurality of anchoring elementsprotruding from a surface of said base member opposite from saidengaging elements, said anchoring elements facilitating molding of saidcomponent into said plastic article.
 3. The component of claim 2 whereinsaid engaging elements and said anchoring elements are integrally moldedwith said base member.
 4. The component of claim 1 wherein saidelastomeric encasement comprises cured plastisol.
 5. The component ofclaim 1 wherein said elastomeric encasement comprises a thermoplasticmaterial.
 6. The component of claim 5 wherein said thermoplasticmaterial is in a set state after being extruded from an extruder, havingsaid engaging elements nipped into said thermoplastic material, andbeing cooled.
 7. The component of claim 1 wherein said magnetizablesubstance comprises ferromagnetic particles disposed within the body ofsaid protective encasement.
 8. The component of claim 1 wherein saidmagnetizable substance comprises a metallic strip associated with saidbase member.
 9. The component of claim 1 wherein said protectiveencasement partially encases said engaging elements such that topsurfaces of said engaging elements are slightly exposed.
 10. A hook orloop component of a hook and loop fastener which can be integrallymolded into a plastic article by a molding process, said hook or loopcomponent comprisinga fastener element having a base member and aplurality of engaging elements upstanding from a surface thereof, and aremovable, elastomeric protective encasement having said engagingelements embedded therein, said protective encasement partially encasingsaid engaging elements such that top surfaces of said engaging elementsare slightly exposed, said protective encasement being removable fromsaid engaging elements so as to expose said engaging elements withoutpermanently deforming said engaging elements or substantially destroyingfastening performance of said engaging elements.
 11. The component ofclaim 10, said fastener element further comprising a plurality ofanchoring elements protruding from a surface of said base memberopposite from said engaging elements, said anchoring elementsfacilitating molding of said component into said plastic article. 12.The component of claim 11 wherein said engaging elements and saidanchoring elements are integrally molded with said base member.
 13. Thecomponent of claim 10 wherein said elastomeric encasement has a tensilestrength of at least 200 pounds per square inch.
 14. The component ofclaim 13 wherein said elastomeric encasement has a tensile strength onthe order of 700 pounds per square inch.
 15. The component of claim 10wherein said elastomeric encasement has an elongation of at least 100%.16. The component of claim 15 wherein said elastomeric encasement has anelongation on the order of 400%.
 17. A fastener of the hook and looptype intended to be incorporated into plastic articles by plasticmolding processes comprising a separable fastener member having a basemember and a plurality of engaging elements upstanding from one surfacethereof; means for covering and intimately surrounding and encasing saidengaging elements, adapted to protect said elements when exposed to theharsh environment of a molding process, said means being removable fromthe fastener after the molding process to expose said engaging elementswithout substantially destroying the performance thereof, the means forcovering and intimately surrounding and encasing the engaging elementsincluding magnetizable means.
 18. The fastener according to claim 17wherein the magnetizable means is a ferromagnetic substance.
 19. Thefastener according to claim 18 wherein the ferromagnetic substancerepresents at least 1% of the weight of the covering.
 20. The fasteneraccording to claim 19 wherein the ferromagnetic substance representsbetween 15% and 25%, inclusive, of the weight of the covering.
 21. Afastener of the hook and loop type intended to be incorporated intoplastic articles by plastic molding processes comprising a separablefastener member having a base member and a plurality of engagingelements upstanding from one surface thereof, elastomeric protectivemeans covering and at least partially surrounding and filling the spacebetween said engaging elements, adapted to protect said elements whenexposed to the harsh environment of a molding process, said protectivemeans being adapted to be removed from the fastener after the moldingprocess to expose said engaging elements without substantiallydestroying the performance of said elements, the elastomeric means forcovering and at least partially surrounding the upstanding elementsincluding magnetizable means.
 22. The separable fastener of claim 21wherein the elastomeric protective means which partially surrounds andfills the space between the engaging elements is an elastomericcomposition which can be applied as a flowable composition and cured toan elastomer in place.
 23. A fastener of the hook and loop type intendedto be incorporated into plastic articles by plastic molding processescomprising a separable fastener member having a base member and aplurality of individual engaging elements upstanding from one surfacethereof; means for partially encasing said individual engaging elementssuch that top surfaces of said engaging elements are slightly exposed,said means adapted to protect said elements when exposed to the harshenvironment of a molding process, said means being removable from thefastener after the molding process to expose said engaging elementswithout substantially destroying the performance thereof, said means forpartially encasing said engaging elements being an elastomericcomposition which fills the volume surrounding the elements and can becured to an elastomer, said elastomeric composition having incorporatedtherein a magnetic attractant.
 24. The component of claim 23 whereinsaid elastomeric encasement is in a foamed condition.
 25. A fastener ofthe hook and loop type intended to be incorporated into plastic articlesby plastic molding processes comprising a separable fastener memberhaving a base member and a plurality of individual engaging elementsupstanding from one surface thereof; means for partially encasing saidindividual engaging elements such that top surfaces of said engagingelements are slightly exposed, said means adapted to protect saidelements when exposed to the harsh environment of a molding process,said means being removable from the fastener after the molding processto expose said engaging elements without substantially destroying theperformance thereof, said means for partially encasing the engagingelements including magnetizable means, said magnetizable means being aferromagnetic substance.
 26. The fastener according to claim 25 whereinthe ferromagnetic substance represents at least 1% of the weight of thecovering.
 27. The fastener according to claim 26 wherein theferromagnetic substance represents between 15% and 25%, inclusive, ofthe weight of the covering.
 28. A fastener of the hook and loop typeintended to be incorporated into plastic articles by plastic moldingprocesses comprising a separable fastener member having a base memberand a plurality of individual engaging elements upstanding from onesurface thereof, elastomeric protective means partially covering andsurrounding the engaging elements such that top surfaces of saidengaging elements are slightly exposed, said protective means adapted toprotect said elements when exposed to the harsh environment of a moldingprocess, said protective means being adapted to be removed from thefastener after the molding process to expose said engaging elementswithout substantially destroying the performance of said elements, saidelastomeric protective means for covering and at least partiallysurrounding the upstanding elements including magnetizable means.
 29. Afastener of the hook and loop type intended to be incorporated intoplastic articles by plastic molding processes comprising a separablefastener member having a base member and a plurality of individualengaging elements upstanding from one surface thereof, elastomericprotective means partially covering and surrounding the engagingelements and filling the space between said individual engaging elementssuch that top surfaces of said engaging elements are slightly exposed,said protective means adapted to protect said elements when exposed tothe harsh environment of a molding process, said protective means beingadapted to be removed from the fastener after the molding process toexpose said engaging elements without substantially destroying theperformance of said elements, said elastomeric protective means havingincorporated therein a magnetic attractant.
 30. The fastener accordingto claim 29 wherein the magnetic attractant is a ferromagneticsubstance.
 31. The fastener according to claim 30 wherein theferromagnetic substance represents at least 1% of the weight of theelastomeric protective means.
 32. The fastener according to claim 31wherein the ferromagnetic substance represents between 15% and 25%,inclusive, of the weight of the covering.